In an image forming apparatus which is configured to rotate a supply roller (manual supply roller) and to thus sandwich a recording sheet by the supply roller when the recording sheet is inserted in an opening (manual supply opening) of an apparatus main body, there has been suggested an image forming apparatus which drives the supply roller and a fixing device by a same driving source so as to reduce costs (refer to JP-A-2006-301364). In the image forming apparatus, if the fixing device is driven at a state where the fixing device is not sufficiently heated, a problem such as scattering of developer caused due to a low-temperature driving is concerned. Also, when the driving source is started after a temperature of the fixing device is increased to a predetermined fixing temperature, a user should wait with holding the recording sheet inserted in the opening.
In JP-A-2006-301364, the driving source is started and the recording sheet is thus sandwiched by the supply roller once a temperature of the fixing device reaches a temperature higher than a melting point of developer even though the temperature does not reach the predetermined fixing temperature, so that a time period during which the user holds the recording sheet is shortened.
However, according to the above technique, it is still necessary for the user to hold the recording sheet inserted in the opening at least until the temperature of the fixing device reaches the temperature higher than the melting point of the developer. Therefore, it is demanded to improve the operability when using a manual feeding.